Add unit test for runScriptAtPath method.

	For mocking see:
	- https://github.com/Citytechinc/prosper
	- https://github.com/Citytechinc/aem-groovy-extension/blob/develop/aem-groovy-extension-tests/src/test/groovy/com/citytechinc/aem/groovy/extension/builders/NodeBuilderSpec.groovy
	- https://github.com/Citytechinc/prosper/blob/develop/src/test/groovy/com/citytechinc/aem/prosper/specs/ProsperSpecSpec.groovy